title: Lesion conspicuity and efficiency of CT colonography with electronic cleansing based on a three-material transition model.
abstract: OBJECTIVE
  The purpose of this article is to report the effect on lesion conspicuity and the practical efficiency of electronic cleansing for CT colonography (CTC).
  
  
  METHODS
  Patients were included from the Walter Reed Army Medical Center public database. All patients had undergone extensive bowel preparation with fecal tagging. A primary 3D display method was used. For study I, the data consisted of all patients with polyps > or = 6 mm. Two experienced CTC observers (observer 1 and observer 2) scored the lesion conspicuity considering supine and prone positions separately. For study II, data consisted of 19 randomly chosen patients from the database. The same observers evaluated the data before and after electronic cleansing. Evaluation time, assessment effort, and observer confidence were recorded.
  
  
  RESULTS
  In study I, there were 59 lesions partly or completely covered by tagged material (to be uncovered by electronic cleansing) and 70 lesions surrounded by air (no electronic cleansing required). The conspicuity did not differ significantly between lesions that were uncovered by electronic cleansing and lesions surrounded by air (observer 1, p < 0.5; observer 2, p < 0.6). In study II, the median evaluation time per patient after electronic cleansing was significantly shorter than for original data (observer 1, 20 reduced to 12 minutes; observer 2, 17 reduced to 12 minutes). Assessment effort was significantly smaller for both observers (p < 0.0000001), and observer confidence was significantly larger (observer 1, p < 0.007; observer 2, p < 0.0002) after electronic cleansing.
  
  
  CONCLUSIONS
  Lesions uncovered by electronic cleansing have comparable conspicuity with lesions surrounded by air. CTC with electronic cleansing sustains a shorter evaluation time, lower assessment effort, and larger observer confidence than without electronic cleansing.
authors.affiliation: Present address: Clinical Science and Advanced Development, Healthcare Informatics, Philips Medical Systems Nederland, Veenpluis 4-6, 5684 PC, Best, The Netherlands.
authors.forename: Iwo W O
authors.initials: IW
authors.lastname: Serlie
authors.forename: Ayso H
authors.initials: AH
authors.lastname: de Vries
authors.forename: Lucas J
authors.initials: LJ
authors.lastname: van Vliet
authors.forename: Chung Y
authors.initials: CY
authors.lastname: Nio
authors.forename: Roel
authors.initials: R
authors.lastname: Truyen
authors.forename: Jaap
authors.initials: J
authors.lastname: Stoker
authors.forename: Franciscus M
authors.initials: FM
authors.lastname: Vos
mesh_terms: D000388:Air; D000465:Algorithms; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media